android_kernel_xiaomi_sm8350/kernel/dma/debug.c
Kees Cook 0638dcc7e7 treewide: Remove uninitialized_var() usage
commit 3f649ab728cda8038259d8f14492fe400fbab911 upstream.

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-06-09 10:29:01 +02:00

1663 lines
43 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2008 Advanced Micro Devices, Inc.
*
* Author: Joerg Roedel <joerg.roedel@amd.com>
*/
#define pr_fmt(fmt) "DMA-API: " fmt
#include <linux/sched/task_stack.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/sched/task.h>
#include <linux/stacktrace.h>
#include <linux/dma-debug.h>
#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/export.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <asm/sections.h>
#define HASH_SIZE 1024ULL
#define HASH_FN_SHIFT 13
#define HASH_FN_MASK (HASH_SIZE - 1)
#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
/* If the pool runs out, add this many new entries at once */
#define DMA_DEBUG_DYNAMIC_ENTRIES (PAGE_SIZE / sizeof(struct dma_debug_entry))
enum {
dma_debug_single,
dma_debug_sg,
dma_debug_coherent,
dma_debug_resource,
};
enum map_err_types {
MAP_ERR_CHECK_NOT_APPLICABLE,
MAP_ERR_NOT_CHECKED,
MAP_ERR_CHECKED,
};
#define DMA_DEBUG_STACKTRACE_ENTRIES 5
/**
* struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
* @list: node on pre-allocated free_entries list
* @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
* @type: single, page, sg, coherent
* @pfn: page frame of the start address
* @offset: offset of mapping relative to pfn
* @size: length of the mapping
* @direction: enum dma_data_direction
* @sg_call_ents: 'nents' from dma_map_sg
* @sg_mapped_ents: 'mapped_ents' from dma_map_sg
* @map_err_type: track whether dma_mapping_error() was checked
* @stacktrace: support backtraces when a violation is detected
*/
struct dma_debug_entry {
struct list_head list;
struct device *dev;
int type;
unsigned long pfn;
size_t offset;
u64 dev_addr;
u64 size;
int direction;
int sg_call_ents;
int sg_mapped_ents;
enum map_err_types map_err_type;
#ifdef CONFIG_STACKTRACE
unsigned int stack_len;
unsigned long stack_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
#endif
};
typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
struct hash_bucket {
struct list_head list;
spinlock_t lock;
} ____cacheline_aligned_in_smp;
/* Hash list to save the allocated dma addresses */
static struct hash_bucket dma_entry_hash[HASH_SIZE];
/* List of pre-allocated dma_debug_entry's */
static LIST_HEAD(free_entries);
/* Lock for the list above */
static DEFINE_SPINLOCK(free_entries_lock);
/* Global disable flag - will be set in case of an error */
static bool global_disable __read_mostly;
/* Early initialization disable flag, set at the end of dma_debug_init */
static bool dma_debug_initialized __read_mostly;
static inline bool dma_debug_disabled(void)
{
return global_disable || !dma_debug_initialized;
}
/* Global error count */
static u32 error_count;
/* Global error show enable*/
static u32 show_all_errors __read_mostly;
/* Number of errors to show */
static u32 show_num_errors = 1;
static u32 num_free_entries;
static u32 min_free_entries;
static u32 nr_total_entries;
/* number of preallocated entries requested by kernel cmdline */
static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
/* per-driver filter related state */
#define NAME_MAX_LEN 64
static char current_driver_name[NAME_MAX_LEN] __read_mostly;
static struct device_driver *current_driver __read_mostly;
static DEFINE_RWLOCK(driver_name_lock);
static const char *const maperr2str[] = {
[MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
[MAP_ERR_NOT_CHECKED] = "dma map error not checked",
[MAP_ERR_CHECKED] = "dma map error checked",
};
static const char *type2name[] = {
[dma_debug_single] = "single",
[dma_debug_sg] = "scather-gather",
[dma_debug_coherent] = "coherent",
[dma_debug_resource] = "resource",
};
static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
"DMA_FROM_DEVICE", "DMA_NONE" };
/*
* The access to some variables in this macro is racy. We can't use atomic_t
* here because all these variables are exported to debugfs. Some of them even
* writeable. This is also the reason why a lock won't help much. But anyway,
* the races are no big deal. Here is why:
*
* error_count: the addition is racy, but the worst thing that can happen is
* that we don't count some errors
* show_num_errors: the subtraction is racy. Also no big deal because in
* worst case this will result in one warning more in the
* system log than the user configured. This variable is
* writeable via debugfs.
*/
static inline void dump_entry_trace(struct dma_debug_entry *entry)
{
#ifdef CONFIG_STACKTRACE
if (entry) {
pr_warning("Mapped at:\n");
stack_trace_print(entry->stack_entries, entry->stack_len, 0);
}
#endif
}
static bool driver_filter(struct device *dev)
{
struct device_driver *drv;
unsigned long flags;
bool ret;
/* driver filter off */
if (likely(!current_driver_name[0]))
return true;
/* driver filter on and initialized */
if (current_driver && dev && dev->driver == current_driver)
return true;
/* driver filter on, but we can't filter on a NULL device... */
if (!dev)
return false;
if (current_driver || !current_driver_name[0])
return false;
/* driver filter on but not yet initialized */
drv = dev->driver;
if (!drv)
return false;
/* lock to protect against change of current_driver_name */
read_lock_irqsave(&driver_name_lock, flags);
ret = false;
if (drv->name &&
strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
current_driver = drv;
ret = true;
}
read_unlock_irqrestore(&driver_name_lock, flags);
return ret;
}
#define err_printk(dev, entry, format, arg...) do { \
error_count += 1; \
if (driver_filter(dev) && \
(show_all_errors || show_num_errors > 0)) { \
WARN(1, pr_fmt("%s %s: ") format, \
dev ? dev_driver_string(dev) : "NULL", \
dev ? dev_name(dev) : "NULL", ## arg); \
dump_entry_trace(entry); \
} \
if (!show_all_errors && show_num_errors > 0) \
show_num_errors -= 1; \
} while (0);
/*
* Hash related functions
*
* Every DMA-API request is saved into a struct dma_debug_entry. To
* have quick access to these structs they are stored into a hash.
*/
static int hash_fn(struct dma_debug_entry *entry)
{
/*
* Hash function is based on the dma address.
* We use bits 20-27 here as the index into the hash
*/
return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
}
/*
* Request exclusive access to a hash bucket for a given dma_debug_entry.
*/
static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
unsigned long *flags)
__acquires(&dma_entry_hash[idx].lock)
{
int idx = hash_fn(entry);
unsigned long __flags;
spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
*flags = __flags;
return &dma_entry_hash[idx];
}
/*
* Give up exclusive access to the hash bucket
*/
static void put_hash_bucket(struct hash_bucket *bucket,
unsigned long *flags)
__releases(&bucket->lock)
{
unsigned long __flags = *flags;
spin_unlock_irqrestore(&bucket->lock, __flags);
}
static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
{
return ((a->dev_addr == b->dev_addr) &&
(a->dev == b->dev)) ? true : false;
}
static bool containing_match(struct dma_debug_entry *a,
struct dma_debug_entry *b)
{
if (a->dev != b->dev)
return false;
if ((b->dev_addr <= a->dev_addr) &&
((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
return true;
return false;
}
/*
* Search a given entry in the hash bucket list
*/
static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
struct dma_debug_entry *ref,
match_fn match)
{
struct dma_debug_entry *entry, *ret = NULL;
int matches = 0, match_lvl, last_lvl = -1;
list_for_each_entry(entry, &bucket->list, list) {
if (!match(ref, entry))
continue;
/*
* Some drivers map the same physical address multiple
* times. Without a hardware IOMMU this results in the
* same device addresses being put into the dma-debug
* hash multiple times too. This can result in false
* positives being reported. Therefore we implement a
* best-fit algorithm here which returns the entry from
* the hash which fits best to the reference value
* instead of the first-fit.
*/
matches += 1;
match_lvl = 0;
entry->size == ref->size ? ++match_lvl : 0;
entry->type == ref->type ? ++match_lvl : 0;
entry->direction == ref->direction ? ++match_lvl : 0;
entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
if (match_lvl == 4) {
/* perfect-fit - return the result */
return entry;
} else if (match_lvl > last_lvl) {
/*
* We found an entry that fits better then the
* previous one or it is the 1st match.
*/
last_lvl = match_lvl;
ret = entry;
}
}
/*
* If we have multiple matches but no perfect-fit, just return
* NULL.
*/
ret = (matches == 1) ? ret : NULL;
return ret;
}
static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
struct dma_debug_entry *ref)
{
return __hash_bucket_find(bucket, ref, exact_match);
}
static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
struct dma_debug_entry *ref,
unsigned long *flags)
{
unsigned int max_range = dma_get_max_seg_size(ref->dev);
struct dma_debug_entry *entry, index = *ref;
unsigned int range = 0;
while (range <= max_range) {
entry = __hash_bucket_find(*bucket, ref, containing_match);
if (entry)
return entry;
/*
* Nothing found, go back a hash bucket
*/
put_hash_bucket(*bucket, flags);
range += (1 << HASH_FN_SHIFT);
index.dev_addr -= (1 << HASH_FN_SHIFT);
*bucket = get_hash_bucket(&index, flags);
}
return NULL;
}
/*
* Add an entry to a hash bucket
*/
static void hash_bucket_add(struct hash_bucket *bucket,
struct dma_debug_entry *entry)
{
list_add_tail(&entry->list, &bucket->list);
}
/*
* Remove entry from a hash bucket list
*/
static void hash_bucket_del(struct dma_debug_entry *entry)
{
list_del(&entry->list);
}
static unsigned long long phys_addr(struct dma_debug_entry *entry)
{
if (entry->type == dma_debug_resource)
return __pfn_to_phys(entry->pfn) + entry->offset;
return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
}
/*
* Dump mapping entries for debugging purposes
*/
void debug_dma_dump_mappings(struct device *dev)
{
int idx;
for (idx = 0; idx < HASH_SIZE; idx++) {
struct hash_bucket *bucket = &dma_entry_hash[idx];
struct dma_debug_entry *entry;
unsigned long flags;
spin_lock_irqsave(&bucket->lock, flags);
list_for_each_entry(entry, &bucket->list, list) {
if (!dev || dev == entry->dev) {
dev_info(entry->dev,
"%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
type2name[entry->type], idx,
phys_addr(entry), entry->pfn,
entry->dev_addr, entry->size,
dir2name[entry->direction],
maperr2str[entry->map_err_type]);
}
}
spin_unlock_irqrestore(&bucket->lock, flags);
cond_resched();
}
}
/*
* For each mapping (initial cacheline in the case of
* dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
* scatterlist, or the cacheline specified in dma_map_single) insert
* into this tree using the cacheline as the key. At
* dma_unmap_{single|sg|page} or dma_free_coherent delete the entry. If
* the entry already exists at insertion time add a tag as a reference
* count for the overlapping mappings. For now, the overlap tracking
* just ensures that 'unmaps' balance 'maps' before marking the
* cacheline idle, but we should also be flagging overlaps as an API
* violation.
*
* Memory usage is mostly constrained by the maximum number of available
* dma-debug entries in that we need a free dma_debug_entry before
* inserting into the tree. In the case of dma_map_page and
* dma_alloc_coherent there is only one dma_debug_entry and one
* dma_active_cacheline entry to track per event. dma_map_sg(), on the
* other hand, consumes a single dma_debug_entry, but inserts 'nents'
* entries into the tree.
*
* At any time debug_dma_assert_idle() can be called to trigger a
* warning if any cachelines in the given page are in the active set.
*/
static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC);
static DEFINE_SPINLOCK(radix_lock);
#define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
#define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
#define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
{
return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
(entry->offset >> L1_CACHE_SHIFT);
}
static int active_cacheline_read_overlap(phys_addr_t cln)
{
int overlap = 0, i;
for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
overlap |= 1 << i;
return overlap;
}
static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
{
int i;
if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
return overlap;
for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
if (overlap & 1 << i)
radix_tree_tag_set(&dma_active_cacheline, cln, i);
else
radix_tree_tag_clear(&dma_active_cacheline, cln, i);
return overlap;
}
static void active_cacheline_inc_overlap(phys_addr_t cln)
{
int overlap = active_cacheline_read_overlap(cln);
overlap = active_cacheline_set_overlap(cln, ++overlap);
/* If we overflowed the overlap counter then we're potentially
* leaking dma-mappings. Otherwise, if maps and unmaps are
* balanced then this overflow may cause false negatives in
* debug_dma_assert_idle() as the cacheline may be marked idle
* prematurely.
*/
WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
}
static int active_cacheline_dec_overlap(phys_addr_t cln)
{
int overlap = active_cacheline_read_overlap(cln);
return active_cacheline_set_overlap(cln, --overlap);
}
static int active_cacheline_insert(struct dma_debug_entry *entry)
{
phys_addr_t cln = to_cacheline_number(entry);
unsigned long flags;
int rc;
/* If the device is not writing memory then we don't have any
* concerns about the cpu consuming stale data. This mitigates
* legitimate usages of overlapping mappings.
*/
if (entry->direction == DMA_TO_DEVICE)
return 0;
spin_lock_irqsave(&radix_lock, flags);
rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
if (rc == -EEXIST)
active_cacheline_inc_overlap(cln);
spin_unlock_irqrestore(&radix_lock, flags);
return rc;
}
static void active_cacheline_remove(struct dma_debug_entry *entry)
{
phys_addr_t cln = to_cacheline_number(entry);
unsigned long flags;
/* ...mirror the insert case */
if (entry->direction == DMA_TO_DEVICE)
return;
spin_lock_irqsave(&radix_lock, flags);
/* since we are counting overlaps the final put of the
* cacheline will occur when the overlap count is 0.
* active_cacheline_dec_overlap() returns -1 in that case
*/
if (active_cacheline_dec_overlap(cln) < 0)
radix_tree_delete(&dma_active_cacheline, cln);
spin_unlock_irqrestore(&radix_lock, flags);
}
/**
* debug_dma_assert_idle() - assert that a page is not undergoing dma
* @page: page to lookup in the dma_active_cacheline tree
*
* Place a call to this routine in cases where the cpu touching the page
* before the dma completes (page is dma_unmapped) will lead to data
* corruption.
*/
void debug_dma_assert_idle(struct page *page)
{
static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
struct dma_debug_entry *entry = NULL;
void **results = (void **) &ents;
unsigned int nents, i;
unsigned long flags;
phys_addr_t cln;
if (dma_debug_disabled())
return;
if (!page)
return;
cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
spin_lock_irqsave(&radix_lock, flags);
nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
CACHELINES_PER_PAGE);
for (i = 0; i < nents; i++) {
phys_addr_t ent_cln = to_cacheline_number(ents[i]);
if (ent_cln == cln) {
entry = ents[i];
break;
} else if (ent_cln >= cln + CACHELINES_PER_PAGE)
break;
}
spin_unlock_irqrestore(&radix_lock, flags);
if (!entry)
return;
cln = to_cacheline_number(entry);
err_printk(entry->dev, entry,
"cpu touching an active dma mapped cacheline [cln=%pa]\n",
&cln);
}
/*
* Wrapper function for adding an entry to the hash.
* This function takes care of locking itself.
*/
static void add_dma_entry(struct dma_debug_entry *entry)
{
struct hash_bucket *bucket;
unsigned long flags;
int rc;
bucket = get_hash_bucket(entry, &flags);
hash_bucket_add(bucket, entry);
put_hash_bucket(bucket, &flags);
rc = active_cacheline_insert(entry);
if (rc == -ENOMEM) {
pr_err_once("cacheline tracking ENOMEM, dma-debug disabled\n");
global_disable = true;
}
/* TODO: report -EEXIST errors here as overlapping mappings are
* not supported by the DMA API
*/
}
static int dma_debug_create_entries(gfp_t gfp)
{
struct dma_debug_entry *entry;
int i;
entry = (void *)get_zeroed_page(gfp);
if (!entry)
return -ENOMEM;
for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
list_add_tail(&entry[i].list, &free_entries);
num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
return 0;
}
static struct dma_debug_entry *__dma_entry_alloc(void)
{
struct dma_debug_entry *entry;
entry = list_entry(free_entries.next, struct dma_debug_entry, list);
list_del(&entry->list);
memset(entry, 0, sizeof(*entry));
num_free_entries -= 1;
if (num_free_entries < min_free_entries)
min_free_entries = num_free_entries;
return entry;
}
void __dma_entry_alloc_check_leak(void)
{
u32 tmp = nr_total_entries % nr_prealloc_entries;
/* Shout each time we tick over some multiple of the initial pool */
if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
nr_total_entries,
(nr_total_entries / nr_prealloc_entries));
}
}
/* struct dma_entry allocator
*
* The next two functions implement the allocator for
* struct dma_debug_entries.
*/
static struct dma_debug_entry *dma_entry_alloc(void)
{
struct dma_debug_entry *entry;
unsigned long flags;
spin_lock_irqsave(&free_entries_lock, flags);
if (num_free_entries == 0) {
if (dma_debug_create_entries(GFP_ATOMIC)) {
global_disable = true;
spin_unlock_irqrestore(&free_entries_lock, flags);
pr_err("debugging out of memory - disabling\n");
return NULL;
}
__dma_entry_alloc_check_leak();
}
entry = __dma_entry_alloc();
spin_unlock_irqrestore(&free_entries_lock, flags);
#ifdef CONFIG_STACKTRACE
entry->stack_len = stack_trace_save(entry->stack_entries,
ARRAY_SIZE(entry->stack_entries),
1);
#endif
return entry;
}
static void dma_entry_free(struct dma_debug_entry *entry)
{
unsigned long flags;
active_cacheline_remove(entry);
/*
* add to beginning of the list - this way the entries are
* more likely cache hot when they are reallocated.
*/
spin_lock_irqsave(&free_entries_lock, flags);
list_add(&entry->list, &free_entries);
num_free_entries += 1;
spin_unlock_irqrestore(&free_entries_lock, flags);
}
/*
* DMA-API debugging init code
*
* The init code does two things:
* 1. Initialize core data structures
* 2. Preallocate a given number of dma_debug_entry structs
*/
static ssize_t filter_read(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
char buf[NAME_MAX_LEN + 1];
unsigned long flags;
int len;
if (!current_driver_name[0])
return 0;
/*
* We can't copy to userspace directly because current_driver_name can
* only be read under the driver_name_lock with irqs disabled. So
* create a temporary copy first.
*/
read_lock_irqsave(&driver_name_lock, flags);
len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
read_unlock_irqrestore(&driver_name_lock, flags);
return simple_read_from_buffer(user_buf, count, ppos, buf, len);
}
static ssize_t filter_write(struct file *file, const char __user *userbuf,
size_t count, loff_t *ppos)
{
char buf[NAME_MAX_LEN];
unsigned long flags;
size_t len;
int i;
/*
* We can't copy from userspace directly. Access to
* current_driver_name is protected with a write_lock with irqs
* disabled. Since copy_from_user can fault and may sleep we
* need to copy to temporary buffer first
*/
len = min(count, (size_t)(NAME_MAX_LEN - 1));
if (copy_from_user(buf, userbuf, len))
return -EFAULT;
buf[len] = 0;
write_lock_irqsave(&driver_name_lock, flags);
/*
* Now handle the string we got from userspace very carefully.
* The rules are:
* - only use the first token we got
* - token delimiter is everything looking like a space
* character (' ', '\n', '\t' ...)
*
*/
if (!isalnum(buf[0])) {
/*
* If the first character userspace gave us is not
* alphanumerical then assume the filter should be
* switched off.
*/
if (current_driver_name[0])
pr_info("switching off dma-debug driver filter\n");
current_driver_name[0] = 0;
current_driver = NULL;
goto out_unlock;
}
/*
* Now parse out the first token and use it as the name for the
* driver to filter for.
*/
for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
current_driver_name[i] = buf[i];
if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
break;
}
current_driver_name[i] = 0;
current_driver = NULL;
pr_info("enable driver filter for driver [%s]\n",
current_driver_name);
out_unlock:
write_unlock_irqrestore(&driver_name_lock, flags);
return count;
}
static const struct file_operations filter_fops = {
.read = filter_read,
.write = filter_write,
.llseek = default_llseek,
};
static int dump_show(struct seq_file *seq, void *v)
{
int idx;
for (idx = 0; idx < HASH_SIZE; idx++) {
struct hash_bucket *bucket = &dma_entry_hash[idx];
struct dma_debug_entry *entry;
unsigned long flags;
spin_lock_irqsave(&bucket->lock, flags);
list_for_each_entry(entry, &bucket->list, list) {
seq_printf(seq,
"%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
dev_name(entry->dev),
dev_driver_string(entry->dev),
type2name[entry->type], idx,
phys_addr(entry), entry->pfn,
entry->dev_addr, entry->size,
dir2name[entry->direction],
maperr2str[entry->map_err_type]);
}
spin_unlock_irqrestore(&bucket->lock, flags);
}
return 0;
}
DEFINE_SHOW_ATTRIBUTE(dump);
static int __init dma_debug_fs_init(void)
{
struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
debugfs_create_bool("disabled", 0444, dentry, &global_disable);
debugfs_create_u32("error_count", 0444, dentry, &error_count);
debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
return 0;
}
core_initcall_sync(dma_debug_fs_init);
static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
{
struct dma_debug_entry *entry;
unsigned long flags;
int count = 0, i;
for (i = 0; i < HASH_SIZE; ++i) {
spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
if (entry->dev == dev) {
count += 1;
*out_entry = entry;
}
}
spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
}
return count;
}
static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
{
struct device *dev = data;
struct dma_debug_entry *entry;
int count;
if (dma_debug_disabled())
return 0;
switch (action) {
case BUS_NOTIFY_UNBOUND_DRIVER:
count = device_dma_allocations(dev, &entry);
if (count == 0)
break;
err_printk(dev, entry, "device driver has pending "
"DMA allocations while released from device "
"[count=%d]\n"
"One of leaked entries details: "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with %s] [mapped as %s]\n",
count, entry->dev_addr, entry->size,
dir2name[entry->direction], type2name[entry->type]);
break;
default:
break;
}
return 0;
}
void dma_debug_add_bus(struct bus_type *bus)
{
struct notifier_block *nb;
if (dma_debug_disabled())
return;
nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
if (nb == NULL) {
pr_err("dma_debug_add_bus: out of memory\n");
return;
}
nb->notifier_call = dma_debug_device_change;
bus_register_notifier(bus, nb);
}
static int dma_debug_init(void)
{
int i, nr_pages;
/* Do not use dma_debug_initialized here, since we really want to be
* called to set dma_debug_initialized
*/
if (global_disable)
return 0;
for (i = 0; i < HASH_SIZE; ++i) {
INIT_LIST_HEAD(&dma_entry_hash[i].list);
spin_lock_init(&dma_entry_hash[i].lock);
}
nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
for (i = 0; i < nr_pages; ++i)
dma_debug_create_entries(GFP_KERNEL);
if (num_free_entries >= nr_prealloc_entries) {
pr_info("preallocated %d debug entries\n", nr_total_entries);
} else if (num_free_entries > 0) {
pr_warn("%d debug entries requested but only %d allocated\n",
nr_prealloc_entries, nr_total_entries);
} else {
pr_err("debugging out of memory error - disabled\n");
global_disable = true;
return 0;
}
min_free_entries = num_free_entries;
dma_debug_initialized = true;
pr_info("debugging enabled by kernel config\n");
return 0;
}
core_initcall(dma_debug_init);
static __init int dma_debug_cmdline(char *str)
{
if (!str)
return -EINVAL;
if (strncmp(str, "off", 3) == 0) {
pr_info("debugging disabled on kernel command line\n");
global_disable = true;
}
return 1;
}
static __init int dma_debug_entries_cmdline(char *str)
{
if (!str)
return -EINVAL;
if (!get_option(&str, &nr_prealloc_entries))
nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
return 1;
}
__setup("dma_debug=", dma_debug_cmdline);
__setup("dma_debug_entries=", dma_debug_entries_cmdline);
static void check_unmap(struct dma_debug_entry *ref)
{
struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;
bucket = get_hash_bucket(ref, &flags);
entry = bucket_find_exact(bucket, ref);
if (!entry) {
/* must drop lock before calling dma_mapping_error */
put_hash_bucket(bucket, &flags);
if (dma_mapping_error(ref->dev, ref->dev_addr)) {
err_printk(ref->dev, NULL,
"device driver tries to free an "
"invalid DMA memory address\n");
} else {
err_printk(ref->dev, NULL,
"device driver tries to free DMA "
"memory it has not allocated [device "
"address=0x%016llx] [size=%llu bytes]\n",
ref->dev_addr, ref->size);
}
return;
}
if (ref->size != entry->size) {
err_printk(ref->dev, entry, "device driver frees "
"DMA memory with different size "
"[device address=0x%016llx] [map size=%llu bytes] "
"[unmap size=%llu bytes]\n",
ref->dev_addr, entry->size, ref->size);
}
if (ref->type != entry->type) {
err_printk(ref->dev, entry, "device driver frees "
"DMA memory with wrong function "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped as %s] [unmapped as %s]\n",
ref->dev_addr, ref->size,
type2name[entry->type], type2name[ref->type]);
} else if ((entry->type == dma_debug_coherent) &&
(phys_addr(ref) != phys_addr(entry))) {
err_printk(ref->dev, entry, "device driver frees "
"DMA memory with different CPU address "
"[device address=0x%016llx] [size=%llu bytes] "
"[cpu alloc address=0x%016llx] "
"[cpu free address=0x%016llx]",
ref->dev_addr, ref->size,
phys_addr(entry),
phys_addr(ref));
}
if (ref->sg_call_ents && ref->type == dma_debug_sg &&
ref->sg_call_ents != entry->sg_call_ents) {
err_printk(ref->dev, entry, "device driver frees "
"DMA sg list with different entry count "
"[map count=%d] [unmap count=%d]\n",
entry->sg_call_ents, ref->sg_call_ents);
}
/*
* This may be no bug in reality - but most implementations of the
* DMA API don't handle this properly, so check for it here
*/
if (ref->direction != entry->direction) {
err_printk(ref->dev, entry, "device driver frees "
"DMA memory with different direction "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with %s] [unmapped with %s]\n",
ref->dev_addr, ref->size,
dir2name[entry->direction],
dir2name[ref->direction]);
}
/*
* Drivers should use dma_mapping_error() to check the returned
* addresses of dma_map_single() and dma_map_page().
* If not, print this warning message. See Documentation/DMA-API.txt.
*/
if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
err_printk(ref->dev, entry,
"device driver failed to check map error"
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped as %s]",
ref->dev_addr, ref->size,
type2name[entry->type]);
}
hash_bucket_del(entry);
dma_entry_free(entry);
put_hash_bucket(bucket, &flags);
}
static void check_for_stack(struct device *dev,
struct page *page, size_t offset)
{
void *addr;
struct vm_struct *stack_vm_area = task_stack_vm_area(current);
if (!stack_vm_area) {
/* Stack is direct-mapped. */
if (PageHighMem(page))
return;
addr = page_address(page) + offset;
if (object_is_on_stack(addr))
err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
} else {
/* Stack is vmalloced. */
int i;
for (i = 0; i < stack_vm_area->nr_pages; i++) {
if (page != stack_vm_area->pages[i])
continue;
addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
break;
}
}
}
static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
{
unsigned long a1 = (unsigned long)addr;
unsigned long b1 = a1 + len;
unsigned long a2 = (unsigned long)start;
unsigned long b2 = (unsigned long)end;
return !(b1 <= a2 || a1 >= b2);
}
static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
{
if (overlap(addr, len, _stext, _etext) ||
overlap(addr, len, __start_rodata, __end_rodata))
err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
}
static void check_sync(struct device *dev,
struct dma_debug_entry *ref,
bool to_cpu)
{
struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;
bucket = get_hash_bucket(ref, &flags);
entry = bucket_find_contain(&bucket, ref, &flags);
if (!entry) {
err_printk(dev, NULL, "device driver tries "
"to sync DMA memory it has not allocated "
"[device address=0x%016llx] [size=%llu bytes]\n",
(unsigned long long)ref->dev_addr, ref->size);
goto out;
}
if (ref->size > entry->size) {
err_printk(dev, entry, "device driver syncs"
" DMA memory outside allocated range "
"[device address=0x%016llx] "
"[allocation size=%llu bytes] "
"[sync offset+size=%llu]\n",
entry->dev_addr, entry->size,
ref->size);
}
if (entry->direction == DMA_BIDIRECTIONAL)
goto out;
if (ref->direction != entry->direction) {
err_printk(dev, entry, "device driver syncs "
"DMA memory with different direction "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with %s] [synced with %s]\n",
(unsigned long long)ref->dev_addr, entry->size,
dir2name[entry->direction],
dir2name[ref->direction]);
}
if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
!(ref->direction == DMA_TO_DEVICE))
err_printk(dev, entry, "device driver syncs "
"device read-only DMA memory for cpu "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with %s] [synced with %s]\n",
(unsigned long long)ref->dev_addr, entry->size,
dir2name[entry->direction],
dir2name[ref->direction]);
if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
!(ref->direction == DMA_FROM_DEVICE))
err_printk(dev, entry, "device driver syncs "
"device write-only DMA memory to device "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with %s] [synced with %s]\n",
(unsigned long long)ref->dev_addr, entry->size,
dir2name[entry->direction],
dir2name[ref->direction]);
if (ref->sg_call_ents && ref->type == dma_debug_sg &&
ref->sg_call_ents != entry->sg_call_ents) {
err_printk(ref->dev, entry, "device driver syncs "
"DMA sg list with different entry count "
"[map count=%d] [sync count=%d]\n",
entry->sg_call_ents, ref->sg_call_ents);
}
out:
put_hash_bucket(bucket, &flags);
}
static void check_sg_segment(struct device *dev, struct scatterlist *sg)
{
#ifdef CONFIG_DMA_API_DEBUG_SG
unsigned int max_seg = dma_get_max_seg_size(dev);
u64 start, end, boundary = dma_get_seg_boundary(dev);
/*
* Either the driver forgot to set dma_parms appropriately, or
* whoever generated the list forgot to check them.
*/
if (sg->length > max_seg)
err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
sg->length, max_seg);
/*
* In some cases this could potentially be the DMA API
* implementation's fault, but it would usually imply that
* the scatterlist was built inappropriately to begin with.
*/
start = sg_dma_address(sg);
end = start + sg_dma_len(sg) - 1;
if ((start ^ end) & ~boundary)
err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
start, end, boundary);
#endif
}
void debug_dma_map_single(struct device *dev, const void *addr,
unsigned long len)
{
if (unlikely(dma_debug_disabled()))
return;
if (!virt_addr_valid(addr))
err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
addr, len);
if (is_vmalloc_addr(addr))
err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
addr, len);
}
EXPORT_SYMBOL(debug_dma_map_single);
void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
size_t size, int direction, dma_addr_t dma_addr)
{
struct dma_debug_entry *entry;
if (unlikely(dma_debug_disabled()))
return;
if (dma_mapping_error(dev, dma_addr))
return;
entry = dma_entry_alloc();
if (!entry)
return;
entry->dev = dev;
entry->type = dma_debug_single;
entry->pfn = page_to_pfn(page);
entry->offset = offset,
entry->dev_addr = dma_addr;
entry->size = size;
entry->direction = direction;
entry->map_err_type = MAP_ERR_NOT_CHECKED;
check_for_stack(dev, page, offset);
if (!PageHighMem(page)) {
void *addr = page_address(page) + offset;
check_for_illegal_area(dev, addr, size);
}
add_dma_entry(entry);
}
EXPORT_SYMBOL(debug_dma_map_page);
void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
struct dma_debug_entry ref;
struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;
if (unlikely(dma_debug_disabled()))
return;
ref.dev = dev;
ref.dev_addr = dma_addr;
bucket = get_hash_bucket(&ref, &flags);
list_for_each_entry(entry, &bucket->list, list) {
if (!exact_match(&ref, entry))
continue;
/*
* The same physical address can be mapped multiple
* times. Without a hardware IOMMU this results in the
* same device addresses being put into the dma-debug
* hash multiple times too. This can result in false
* positives being reported. Therefore we implement a
* best-fit algorithm here which updates the first entry
* from the hash which fits the reference value and is
* not currently listed as being checked.
*/
if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
entry->map_err_type = MAP_ERR_CHECKED;
break;
}
}
put_hash_bucket(bucket, &flags);
}
EXPORT_SYMBOL(debug_dma_mapping_error);
void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction)
{
struct dma_debug_entry ref = {
.type = dma_debug_single,
.dev = dev,
.dev_addr = addr,
.size = size,
.direction = direction,
};
if (unlikely(dma_debug_disabled()))
return;
check_unmap(&ref);
}
EXPORT_SYMBOL(debug_dma_unmap_page);
void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, int mapped_ents, int direction)
{
struct dma_debug_entry *entry;
struct scatterlist *s;
int i;
if (unlikely(dma_debug_disabled()))
return;
for_each_sg(sg, s, nents, i) {
check_for_stack(dev, sg_page(s), s->offset);
if (!PageHighMem(sg_page(s)))
check_for_illegal_area(dev, sg_virt(s), s->length);
}
for_each_sg(sg, s, mapped_ents, i) {
entry = dma_entry_alloc();
if (!entry)
return;
entry->type = dma_debug_sg;
entry->dev = dev;
entry->pfn = page_to_pfn(sg_page(s));
entry->offset = s->offset,
entry->size = sg_dma_len(s);
entry->dev_addr = sg_dma_address(s);
entry->direction = direction;
entry->sg_call_ents = nents;
entry->sg_mapped_ents = mapped_ents;
check_sg_segment(dev, s);
add_dma_entry(entry);
}
}
EXPORT_SYMBOL(debug_dma_map_sg);
static int get_nr_mapped_entries(struct device *dev,
struct dma_debug_entry *ref)
{
struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;
int mapped_ents;
bucket = get_hash_bucket(ref, &flags);
entry = bucket_find_exact(bucket, ref);
mapped_ents = 0;
if (entry)
mapped_ents = entry->sg_mapped_ents;
put_hash_bucket(bucket, &flags);
return mapped_ents;
}
void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
int nelems, int dir)
{
struct scatterlist *s;
int mapped_ents = 0, i;
if (unlikely(dma_debug_disabled()))
return;
for_each_sg(sglist, s, nelems, i) {
struct dma_debug_entry ref = {
.type = dma_debug_sg,
.dev = dev,
.pfn = page_to_pfn(sg_page(s)),
.offset = s->offset,
.dev_addr = sg_dma_address(s),
.size = sg_dma_len(s),
.direction = dir,
.sg_call_ents = nelems,
};
if (mapped_ents && i >= mapped_ents)
break;
if (!i)
mapped_ents = get_nr_mapped_entries(dev, &ref);
check_unmap(&ref);
}
}
EXPORT_SYMBOL(debug_dma_unmap_sg);
void debug_dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t dma_addr, void *virt)
{
struct dma_debug_entry *entry;
if (unlikely(dma_debug_disabled()))
return;
if (unlikely(virt == NULL))
return;
/* handle vmalloc and linear addresses */
if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
return;
entry = dma_entry_alloc();
if (!entry)
return;
entry->type = dma_debug_coherent;
entry->dev = dev;
entry->offset = offset_in_page(virt);
entry->size = size;
entry->dev_addr = dma_addr;
entry->direction = DMA_BIDIRECTIONAL;
if (is_vmalloc_addr(virt))
entry->pfn = vmalloc_to_pfn(virt);
else
entry->pfn = page_to_pfn(virt_to_page(virt));
add_dma_entry(entry);
}
void debug_dma_free_coherent(struct device *dev, size_t size,
void *virt, dma_addr_t addr)
{
struct dma_debug_entry ref = {
.type = dma_debug_coherent,
.dev = dev,
.offset = offset_in_page(virt),
.dev_addr = addr,
.size = size,
.direction = DMA_BIDIRECTIONAL,
};
/* handle vmalloc and linear addresses */
if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
return;
if (is_vmalloc_addr(virt))
ref.pfn = vmalloc_to_pfn(virt);
else
ref.pfn = page_to_pfn(virt_to_page(virt));
if (unlikely(dma_debug_disabled()))
return;
check_unmap(&ref);
}
void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
int direction, dma_addr_t dma_addr)
{
struct dma_debug_entry *entry;
if (unlikely(dma_debug_disabled()))
return;
entry = dma_entry_alloc();
if (!entry)
return;
entry->type = dma_debug_resource;
entry->dev = dev;
entry->pfn = PHYS_PFN(addr);
entry->offset = offset_in_page(addr);
entry->size = size;
entry->dev_addr = dma_addr;
entry->direction = direction;
entry->map_err_type = MAP_ERR_NOT_CHECKED;
add_dma_entry(entry);
}
EXPORT_SYMBOL(debug_dma_map_resource);
void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
size_t size, int direction)
{
struct dma_debug_entry ref = {
.type = dma_debug_resource,
.dev = dev,
.dev_addr = dma_addr,
.size = size,
.direction = direction,
};
if (unlikely(dma_debug_disabled()))
return;
check_unmap(&ref);
}
EXPORT_SYMBOL(debug_dma_unmap_resource);
void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
size_t size, int direction)
{
struct dma_debug_entry ref;
if (unlikely(dma_debug_disabled()))
return;
ref.type = dma_debug_single;
ref.dev = dev;
ref.dev_addr = dma_handle;
ref.size = size;
ref.direction = direction;
ref.sg_call_ents = 0;
check_sync(dev, &ref, true);
}
EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
void debug_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size,
int direction)
{
struct dma_debug_entry ref;
if (unlikely(dma_debug_disabled()))
return;
ref.type = dma_debug_single;
ref.dev = dev;
ref.dev_addr = dma_handle;
ref.size = size;
ref.direction = direction;
ref.sg_call_ents = 0;
check_sync(dev, &ref, false);
}
EXPORT_SYMBOL(debug_dma_sync_single_for_device);
void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
int nelems, int direction)
{
struct scatterlist *s;
int mapped_ents = 0, i;
if (unlikely(dma_debug_disabled()))
return;
for_each_sg(sg, s, nelems, i) {
struct dma_debug_entry ref = {
.type = dma_debug_sg,
.dev = dev,
.pfn = page_to_pfn(sg_page(s)),
.offset = s->offset,
.dev_addr = sg_dma_address(s),
.size = sg_dma_len(s),
.direction = direction,
.sg_call_ents = nelems,
};
if (!i)
mapped_ents = get_nr_mapped_entries(dev, &ref);
if (i >= mapped_ents)
break;
check_sync(dev, &ref, true);
}
}
EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int nelems, int direction)
{
struct scatterlist *s;
int mapped_ents = 0, i;
if (unlikely(dma_debug_disabled()))
return;
for_each_sg(sg, s, nelems, i) {
struct dma_debug_entry ref = {
.type = dma_debug_sg,
.dev = dev,
.pfn = page_to_pfn(sg_page(s)),
.offset = s->offset,
.dev_addr = sg_dma_address(s),
.size = sg_dma_len(s),
.direction = direction,
.sg_call_ents = nelems,
};
if (!i)
mapped_ents = get_nr_mapped_entries(dev, &ref);
if (i >= mapped_ents)
break;
check_sync(dev, &ref, false);
}
}
EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
static int __init dma_debug_driver_setup(char *str)
{
int i;
for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
current_driver_name[i] = *str;
if (*str == 0)
break;
}
if (current_driver_name[0])
pr_info("enable driver filter for driver [%s]\n",
current_driver_name);
return 1;
}
__setup("dma_debug_driver=", dma_debug_driver_setup);